A nonlocal cascade model for anisotropic magnetohydrodynamic (MHD) turbulence in the presence of a uniform magnetic field B is proposed. The model takes into account that (1) energy cascades in an anisotropic manner, and as a result a different estimate for the cascade rate in the direction parallel and perpendicular to the B field is made, and (2) the interactions that result in the cascade ar...

It is most natural to assume that mysterious Small Ionized and Neutral Structures (SINS) in diffuse ISM arise from turbulence. There are two obvious problem with such an explanation, however. First of all, it is generally believed that at the small scales turbulence should be damped. Second, turbulence with Kolmogorov spectrum cannot be the responsible for the SINS. We consider, however, effect...

In the present work are presented results from numerical simulations performed with the ANSYS-CFX code. It is studied a radial diffuser flow case, which is the main academic problem used to study the flow behavior on flat plate valves. The radial flow inside the diffuser has important behaviors such as the turbulence decay downstream and recirculation regions inside the valve flow channel due t...

The wind loads considerably influence lightweight spatial structures. An example of spatial structures is scallop domes that contain various configurations and forms and the wind impact on a scallop dome is more complex due to its additional curvature. In our work, the wind pressure coefficient (Cp ) on the scallop dome surface is studied numerically and experimentally. Firstly, the programming...

sediment flushing of reservoirs is an operational technique, whereby previously accumulated sediments in the reservoirs are hydraulically removed by accelerated flow when the bottom desiltingoutlets of the dam are opened. in this research, the process of sediment flushing is simulated by a three dimensional numerical model in which sediment and flow interaction are reflected in the reservoirs. ...

In this validation work two turbulence models (k-ε and SST model) and two grids (a finer hybrid grid and a tetrahedral coarser grid) are considered in order to model helium release and dispersion. Simulation results are compared against an experiment of jet release phenomena in the Battelle Model Containment facility (BMC), a multi-compartment facility with a total volume of about 560 m. In the...

Nomenclature a w speed of sound at wall (m/s) D diameter (m) H AW adiabatic enthalpy (J/kg) H w wall enthalpy (J/kg) H 0 total enthalpy (J/kg) h heat transfer coefficient (kg/m 2 /sec), h FR Fay-Riddell heat transfer coefficient (kg/m 2 /sec) M ∞ free stream Mach number M e boundary layer edge Mach number p ∞ free stream pressure (N/m 2) q heat transfer rate (W/m 2) r radial position (m) R base...

The results are reported of an experimental investigation of turbulent flow through a plane sudden expansion of expansion ratio R=D/d=4 and aspect ratio A= w/h=5.33. It is well known that plane sudden expansions with R greater than 1.5 produce asymmetric flows and this was again seen in this study. The literature for the asymmetric situation (R>1.5) is surprisingly limited and only axial veloci...

B = Einstein absorption coefficient E = total energy, P ns s s es 12 uiui , J=m g = electronic state degeneracy H = shape factor, = , dimensionless h = specific enthalpy, J=kg h = Planck’s constant h = enthalpy of formation, J=kg I = radiative intensity,W=cm-sr J = diffusive mass flux, kg=m s Le = Lewis number, dimensionless M = Mach number, dimensionless n = number density, m 3 p = pressure, P...

This paper describes a simulation model that has been used for controller design and stability and performance analysis of a micro X-CELL helicopter as central element of the Autonomous Scout Rotorcraft Testbed (ASRT) developed at Georgia Institute of Technology, Atlanta, USA. The general model, simple, yet comprehensive and efficient for the task at hand, consists of the following elements: he...